The invention is directed to a circuit arrangement for line units of an ATM switching equipment unit operating according to an asynchronous transfer mode (ATM), and wherein the line units are respectively connected to input lines for supply of message cells thereto. Such a circuit arrangement has already been disclosed by European patent application EP 0 500 238 A1. It is stated therein that, among other things, a content-addressable memory is provided in a line unit. This memory is capable of being programmed such that a check for the conversion of logical addresses to physical addresses for hits is carried out only in view of the path identifier, only in view of the call identifier or in view of the path identifier and call identifier, without entering into the evaluation of the identifier information in greater detail for the purpose of a different handling of the virtual connections proceeding in virtual paths.